The present invention relates in general to semiconductor and optoelectronic device fabrication methods and resulting structures. More specifically, the present invention relates to fabrication methods and resulting structures for smoothing the sidewall roughness of a post-etched film.
In contemporary semiconductor device fabrication processes a large number of microelectronic and on-chip photonics devices, such as field effect transistors (FETs) and semiconductor optical waveguides, respectively, are fabricated on a single wafer. FETs are well known in the electronic arts and form the basis of modern integrated circuit design, logic, and memory applications. Semiconductor optical waveguides, on the other hand, are a very important part of modern integrated optoelectronic systems, especially for electrically active devices. Applications range from semiconductor lasers, optical filters, switches, modulators, isolators, and photodetectors. To increase device density, improve performance, and decrease the power load of these devices, device fabricators employ increasingly sophisticated fabrication techniques that include a combination of lithography, sidewall image transfer, spacer imaging and other processes to form final device structures having progressively decreasing critical dimensions.